Process of electroplating



June 7, 1932. o. L. MAAG v 1,861,445

PROCESS OF' ELECTROPLATING Filed April 4. 1927 IIILLUU L UJ if I A q um.

d l J Patented June 7, 1932 UN1TED STATES PATENT OFFICE OSCAR L. MAAG, OF CANTON, OHIO, ASSIGNOR T0 THE ROLLER BEARING COM- PANY, OF CANTON, OHIO, 4A. CORPORATION OF OHIO PROCESS 0F ELECTROPLATING Application led April 4,

My invention relates to electro-plating tubular articles such, for instance, as cones for roller bearings. Heretofore, it has been dicult to make a coating that is entirely smooth and of uniform thickness throughout the interior surface of such article. The principal objects of this invention are to overcome such difficulties and to produce a cheap and practical lprocess of electro-plating the interior surface of hollow articles with a smooth and uniform coating. The invention consists in the process hereinafter described and claimed.

In the accompanying drawing, which forms part of this specification, and wherein like reference numerals refer to like parts whereev-er theyoccur.

' Fig. 1 is a view of an apparatus for carrying out my process;A f, f

Fig. 2 is a horizontal cross section thereon;

Fig. 3 is a horizontal section on the line 3 3 of Fig. 2; and .I Y v Fig. 4 is a detail view o"f the locking device.

The apparatus illustratedin the accompanying drawing illustrates-top yplates 1 and a bottom'plate. 2 secured 'together by rods 3, 4 that are preferably threein number and equidistant from. a common axis. Some (preferably two) of vthese vrods have their ends reduced to pass through holes #provided thereforinthe top and bottom plates respectively, which platesbear againstV the shoulders thus formed on the rods., vThe lower plate has a pair of lugs' extending,'from its margin, and on them ism'ou-nted` a horizontal pintle 6 vthat passes through the flattened lower end of one of the cage rodsvwhereby said rod 4 is pivotally mounted on said lower plate between said lugs. .The upper plate has a pair of outwardly projecting lugs 8 arranged to serve as a guide for the upper end of said pivotal rod and the upper end of this pivotal ro-ol has a notch A9 in its side that permits it to straddle the marginal portion ofthe upper plate. The lugs of said upper plate have in their upper edges slots 10 that inclinedownwardly and outwardly and are of a size to receive the pintle 1l of a cam or bent lever 12. This .bent lever comprises a cam arm 13 and a handlearm 14, the cam arm being slightly 1927. sum1 Nb. 180,828.

side thereof and the handle arm inclines' downwardly on the other side. this` arrangement, the locking device maybe quickly mounted or removed; and when mounted, it

serves to press the pivotal rod into proper engagement with the top plate, the leverage action of the handle arm tending to hold said locking device in position. v

4The top plate has a large hole 15 extending therethrough and located centrally with respect to the cage rods. The lower portion of this hole is of smaller diameter `than the upper portion thereof, thus forming an annular shoulder'l. Extending downwardly through the hole in the top plate is a hollow sleeve 17 whose upper end is provided with a circumferential rib 18 that overlaps said shoulder 16. The lower end of said sleeve has-a screw thread on its outer surface on which is mounted a ring nut 19. Surrounding the sleeve is a helical spring 20, one end of which bears against the lowervsurface of the top plate and the other end of which bears against said ring nut. Opposite said spring Vthe sleeve is provided with radial perforations 21 intended for the escape of the electro-plating duid and the gases generated in the process of electro-plating.

The top surface of the upper plate is recessed to receive aplate 22 through which an insulating bushing 23 extends into the upper portion vof said sleeve. The lower plate has a centrally disposed hole 24 extending therethrough with the lower portion of smaller diameter than the rupper portion to form a shoulder 25 for the support of an insulating bushing 26 that extends through said hole. The lower end of this bushing is screw threaded for engagement with a threaded ring 27 that is provided with a circumferential flange 28 by which it is secured to the lower side of said lower plate. The anode l29 extends through both the upper bushing and the lower bushing, its lower lend being smaller Athan the diameter of the lower bushing so as to leave an annular channel 30 between them. The portion of the anode opposite the upper bushing is provided with i is suitably connected to the top plate, which in turn is electrically connected through the cage rods to the bottom plate so that the cage or holding device, together with the work therein, functions as the cathode.

The appliance hereinbefor described is designed especially for electro-plating the interior of hollow articles such, for instance, as cones 34 for roller bearings which are indicated in broken lines. The spacing of the locking rods is'such that when the parts are locked together, all three bars will be in contact with the periphery of the cones at their larger diameters and such cones will be in centralalinement with each other and with the anode. In assembling such cones, or similar work, the anode is first withdrawn endwise, and the pivotal rod of the cage is released and swung down. The ccnes are then placed' in the cage with the lowermost cone resting on the lower plate with its circumference in contact with the two fixed rods of the cage. The other cones are similarly placed one above the other so as to form a substantially continuous tube, against the uppermost of which the spring presses the sleeve, thereby clamping the assembled cones firmly together. The pivotal rod is then swung into place .and locked with the locking device whereby any cones that may be out of alinement are forced into proper position. The cage thus filled and locked is then placed in the bath and the anode is inserted therein in axial alinement with said cones.

According to the present process,the tubular article is suspended fully submerged into the electrolyte bath 36, in a suitable tank 37 with its axis vertical and with the anode extending entirely through the article at such axis and with the tubular article in contact with the cage which with it constitutes the cathode. The bath has free access to the interior of the article at the lower end thereof through the annular passageway between the anode and the article; and likewise the interior of the article also communicates with the bath at the top of the article by a similar annular passageway. When the electric current is applied, the electrodeposition is effected in a well known manner. In this operation of electrodeposition, bubbles of gas are generated that tend to cling to the surface of the article undergoing plating. According to the present process, however, such surface is substantially vertical and the bubbles generated thereon tend to form abubble column that is considerably lighter than the column of electrolyte, with the result that bubble columns are displaced upwardly by the pressure of the electrolyte operating throu h the annular passageway at the bottom of t e article. The liquid intermingled with such bubbles is carried to the top of the article and thence into the mass of the electrolyte, while the gas contained in such bubble column escapes upwardly to the top surface of the bath. Due to the small sectional area of the top and bottom annular passageways, and the continuous generation of gas bubbles, there is a continuous circulation of the electrolyte upwardly in the interior of the article which removes the gas bubbles almost as soon as they are formed and continuously supplies unspent electrolyte to the interior of the article.

cathode cage rods, produce on t e inner surface of the article a coatingthat is quite smooth and of uniform thickness.

In the electro-plating of the interior of short articles such as cones for roller bearings, itis desirable to assemble them endwise in the form of a continuous tube of such length as may be most convenient and economical to handle. In such pieces, no opening should be left between the articles through which the electrolyte may iiow laterally. In the case of perforated articles, the perforations may be temporarily closed; but preferably such articles or tubular assemblies thereof are placed inside of a hollow shell with inwardly extending flanges at the top and bottom thereof adapted to cut olf the circulation of the electrolyte on the outer surface of the article and thus confine the circulation to the interior of the article.

What I claim is:

1. The improvement in the process of electroplating the interior of short tubular articles which consists in assembling such articles into a continuous tube and submerging such tube in the electrolyte with its axis vertical and with the anode extending entirely therethrough at the axis thereof and sepaated therefrom by an unobstructed annular passageway, the electrolyte having free ingress to the interior of said tube at the botfree egress at the top of said tube to the main electrolyte bath and appl 'ng electric current entirely through sai anode, whereby bubbles are formed at the inner surface of the article with consequent circulation of the electrolyte due to the difference in `specific gravity between the electrolyte outslde of said article and the bubble column inside thereof.

2. The improvement in the rocess of electroplating short tubular artic es which consists in assembling-such articles into a continuous tube, preventing ow through the side of such tube and in suspending such tube below the surface and above the bottom of the bath with its base extendin vertically and v the anode extending entire y through said bore at thecenter thereof and causlng circulation of the bath from the main body thereof upwardly through said bore and thence to the main body thereof, said anode being the only anode.

Signed atACanton, Ohio, this 30th day of March, 1927.

OSCAR L. MAAG. 

